What is Hirschsprung's disease?

Hirschsprung's disease is a congenital condition that affects the large intestine (colon) and causes problems with passing stool. The disease is characterised by the absence of ganglion cells (nerve cells) in segments of the colon, which results in a lack of peristalsis (coordinated muscle contractions that move contents through the intestines) in the affected parts of the colon, causing stool to build up and form a blockage.

What are the symptoms of Hirschsprung's disease?

Hirschsprung's disease often presents shortly after birth, with symptoms becoming more pronounced as the child grows older.

Symptoms in newborns may include:

• failure to pass the first stool (meconium) within 24 to 48 hours after birth
• a swollen abdomen
• green vomit
• severe constipation or episodes of diarrhoea
• feeding difficulties

Symptoms in infants and toddlers may include:

• persistent and severe constipation that doesn’t respond to standard treatments
• continued swelling of the abdomen
• poor weight gain
• enterocolitis, a serious infection of the colon characterised by fever and explosive diarrhoea
• general fatigue and low energy
• reluctance to eat because of abdominal discomfort and bloating

Symptoms in older children may include:

• ongoing constipation that may be associated with a swollen abdomen
• stools that may be narrow and ribbon-like
• poor growth and delayed development
• recurrent episodes of obstruction in the colon requiring medical intervention
• general fatigue and low energy
• reluctance to eat because of abdominal discomfort and bloating

What causes Hirschsprung's disease?

During foetal development, neural crest cells (stem cells) migrate from the neural tube to form various tissues. These neural crest cells are precursors to the ganglion cells in the colon, which are critical for the functioning of the enteric nervous system responsible for peristalsis.

In Hirschsprung's disease, the migration of the neural crest cells is incomplete, causing a segment of the colon to lack the ganglion cells necessary for peristalsis. The lack of peristalsis in the affected parts of the colon can lead to the build-up of stool, resulting in severe constipation and abdominal distension.

The exact cause behind the incomplete migration is still unclear, but several genes have been associated. The most notable ones include mutations in the RET proto-oncogene, mutations in the EDNRB (endothelin receptor B) gene, and mutations in the EDN3 (endothelin 3) gene.

How is Hirschsprung's disease diagnosed?

The diagnosis of Hirschsprung's disease involves a multi-step approach combining clinical evaluation, imaging studies, and a rectal biopsy to confirm the absence of ganglion cells in the affected segment of the colon. The primary steps and methods used for diagnosis include:

• Medical history: The specialist will review the patient's medical history and symptoms, such as chronic constipation, abdominal distension, and feeding difficulties.
• Physical examination: The physical examination will include an abdominal examination and a rectal examination.
• Imaging studies: Imaging studies will include:

       a) A contrast enema (barium enema) X-ray to visualise the structure of the colon.

       b) An anorectal manometry to measure the reflexes of the muscles surrounding the rectum.

• Rectal biopsy: The specialist will perform a rectal biopsy to obtain a tissue sample from the rectum and examine it under a microscope for the presence or absence of ganglion cells.

What is the treatment for Hirschsprung's disease?

The treatment for Hirschsprung's disease is primarily surgical, aimed at removing the non-functional segment of the colon to restore function. The main surgical options available are pull-through procedures, which include:

• Swenson procedure: The non-functional segment is removed, and the healthy colon is pulled through and attached directly to the anus.
• Duhamel procedure: The non-functional segment is bypassed but not removed. The healthy colon is brought down and attached to the rectum, creating a new pathway for stool.
• Soave procedure: The inner lining and submucosa of the non-functional segment are removed, leaving the outer muscular layer intact. The healthy colon is then pulled through this muscular cuff and attached to the anus.

Surgery for Hirschsprung's disease can be performed with a laparoscopic-assisted pull-through, which is a minimally invasive technique where small incisions and a laparoscope are used to perform the pull-through procedure, or a transanal endorectal pull-through, which involves performing the pull-through procedure entirely through the anus without abdominal incisions.

What are the long-term effects of Hirschsprung's disease?

While many children with Hirschsprung's disease lead healthy lives post-surgery, some may face ongoing challenges related to function of the colon and nutrition, such as constipation and the need for nutrition supplementation.

Early diagnosis, ongoing medical care, and appropriate interventions are essential for the effective management and treatment of the condition, preventing complications, improving quality of life, and ensuring growth and development.

Which specialist should I see if I suspect my child has Hirschsprung's disease?

If you suspect your child has Hirschsprung's disease, it’s important to schedule an appointment with your GP as soon as possible. Your GP can initiate the evaluation process and refer you to appropriate specialists for further assessment and management, including gastroenterologists and colorectal surgeons.